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M. TOURNIER MUS ICAL INSTRUMENT April 16, 1929/ 1,709,548

Filed April 29. 1926 .5 Sheets-Sheet 1 A A a? 1 April 16, 1929. M. TOURNIER 1,709,548

' MUSICAL INSTRUMENT Filed April 29, 1926 3 Sheets-Sheet 2 April 1929- M. TOURNIER 1,709,548

MUSICAL INSTRUMENT Filed April 29, 1926 3 Sheets-Sheet 3 prcssed. 'This parallel arrangement of the circuits 'is best adzipted t0 a high-power current source hamg a low resistarice. V

' O ne can also Use as a crreht source '3-electrode "la'm'ps having grid and"plate circuits comprisin vires of high resistane, the com pliiig 'grld platc'being ver tight'and the self-induction havmg'a large distributed'apcit or two' lairxpsmajy be coupled by means of 'capcities and resistances in the mnner of :1n Abraham inultiVibrator sysm. \Vith either of thes arrangements the current source'may lie given a waVe orm correspond ing to the string gmuping desired. An analogous system for synthesizing current of appropriate Wave f01ni consists in employing tl1e periodic discharge from a neon lamp as current source (Fig.'2) To accomplish this, a source of direct current d is provided and (me ofits polos cohnected first to one of the two Plates of a condenser 6 and then to one terminal of neon lamp f. T he other polo of d is nnented through a. 'resistanre g to the other plate of condenser e. ThesecOnd terminal of lan1p is connected thrOugh the primary IL O'ztta1xsf0rmetzt0 tlieother of thetwo plates of condenser (2. The neon lainp resists the passage of cuiTcnt long cnogh topermit the condenser e to becoine charged but when the tension has tiScn snfiiciently, the larnp suddely discharg and tlie cnrrent stored in c fiows tlirougli the primary circuit 7L. The form of discharge curv is shown in Fig. 8. The carr ent flowing in iL may be utilized by means of a sotondary 723 of the above said transformer. The ordinary neon lamp yields a Cltr1ct \vhi(li issomewhat too weak. It mny lie amplifi6d by meahs of 'tlie 3-electrodc lamp i, fed by a main batteryj (the usual battey for tl1e filament is not shown in Fig. 2). The amplified Current thns produced may lJC lcd from the lamp to the electromngnetic Y:bOI'S '6 6 b arranged in series thcrewith, the sWltchcS c 0 0 short circuiting tnc Vib1at0iS When tlre latter are not fnnctioning.

trolled by tlie latter. A current source of this kindis sho-Wn in Fig. 4. It comprises a frame ]a preferably (of aluminium) thebuseof which ecmprrsesa ouralk for ashaft l which can be turncd by means of a wheel Z and a worm Zcontrdlld by a hand wheel 1'. The foregoing elcmonts serve to distend a spring m attached to an iron or similar paramagnetic bar n. Bar 7L is suspended from two cords 0 and 0 :ittached to the top of frame le the cords bei ng able to conduct current from to n. One end of the bar 72 carrios a short, strong elastic elemertt n provided With 21 Contact point of tungsten or similar non-oxidizable matcrial. 1? presses lightly, when the main vibrator n is not in action, against an adjustable screw p provided with a tungsten contact and supported by an insulating block on frame 70. A U-shaped electromagnet is fastened in any appropriatc manner to frnme k and the free onde of the magnot are arranged t0 tcrminate on opposite sides of vibrator n so that the latter, and With it element n may be angularly displaced by the electromagnet 9 if the latter iz: magnetized. n, has a period of Vibraiion which may be adjusted by changing the tension of spring 772 and it is only necessary to establisn :1 circuit from one pole of a battery 8 to the mass of rame le, the current finding a path through 0 or 0 to bar n, part n, contact scrcw p, winding of eleCtromagnet g and back to battery 8 in order to cause bar n t0 vibrato at the desired frequcncy. A second short strong olastic element n is fastened to the bar 71. and comes into contact with an adjnstable screw 7 which is supported by an insnlatin block fastened to frame k. Thc contact n-. a is utilized to control the ennitting of the cnrrcnt to 130 ntilized in the electromagnets placcd ovcr the piano strings.

A complote layont, using the aho\'c descrilmd mechanical Vibrator partially slmwn in Fig. 5. It includes a battery 8 servin lo furnish current to a group 0?, let us sz:y 12 vibraor bars such as '27, and also to actuate tlie electromagnetic vibrators such as 6 placed over the piano strings (Fig. 5 showing only 3 bars 71) all the vibrating bars being connected 0 one pole of battery s (negative) and all be electronmgnctic 9 and conta ct screws 7) to the other polo. The electromagnetie vibrators such as 7) which are placsd above the piano strings 6 are each connccied into a circuit consistng ol tl1e elec troinagnct itself, of a switch (in grand pianos and the lil:.o, tl1e:zc arc connecter? in (hc dampcrs which are displaccd by depressing the l eys), a Wirc canne ted ro a slidable contact 14 (adjustable onto any one of plots connectcd to tl electrodes of the batterys) flic part of battery .9 which romains active be:

yond contact -u (in Fig. it comprises that part of tnc leattery which is to the right et slidable contact 21), one extreme polo of the battery (this polebcing connected to all the vibrating bars a) a bar a, tlic contact elemcnt 77, the contact serew 7* and a return wirc t0 tla. elect-romagnet A single bar n furnishcs current not only to one vibrator 6 for one sound as shovn in Fig. 5, but for instance also to sir; ot-he1S (seven in all) connected in parallel bctwecn contact screw 7* and slidable contact u in tll( manner, shown in Fig. 1. To avoid excessive sparking, a condenser (net shown) may be connected in parallel betneen n and 77 and condenser v between n and As shown in Fig. 5, a resistance 10 may be connected to the condensers a; attaehed aeross n, 1. By suitably choosixig the capacities of condensers 12 and the resistance of elements w this circuit may lie lnade to furnish the harmonie dcsired for any particular electromagnetic rihrator.

lhe vibrators and saritchos may, in a grand piano l,)C arrzmgcd in zigzag lines on a huard placcd tr;msvcrsally ovcr the piano s.;ings. '.llie set et 'ilnrating bars 91 is located in a box which is a distinct part l:om t piano and may oceupy any con- 119 renieht place near the same.

From the preceding description, it Will be clear (ont current source 8 cause bars n to riln-alc witlmut interruption and the clemonts 'n 01" bar 71 will tend to send a periodical curren. into the elactromagnets b. However no current will actually flow into (2 as long as (lie proper piano key is net de.- pressed. An electromagnet 7) on rcceiving of proper periodieal current may vibrato its correspondin string e\'en directly without the interrention of hannncrs or else it may maintain tl;=:* vibration et 111e string: aftcr the lxannner hasstruck the said string. Thr stren;{tli of the aonnd n1aintaining: etl'eet may he regulated by :uljustmcnt of the Slidaole contact u or else by the action of a slid aide contact et a modulating rheostat arran;ud in t'll(. circuit. said slidable contacts lneinpj arrangred to in: moved by the knee or the foot in order to variate the expression o'i tl1e tune produccd.

Although apparatn:: constructed in accordanee \\'ili the foregoing reduces materially lie numlwr et parts heretofore neeessary in apparatus of this kind it still 0fie:s a certain amount of inconvenience on acconnt m" tlsc hall: et the box for the vibrating bars -n. First of all it may be taken into account (ha lllt nulnlwer of :nnpme-tnrns necessary for tl;c vlcrtroxnagznetic rilnrators is far from ncgligihle about 500 ampere-turns l:eing gencra!ly required. Contact 7E, as :1 consoquonre. arc suhjccted o severe usage and must l)c prorided with ratl1er large contacts i. e. with contacts ofabout 3 mm. in diameter and 1 mm. in thiekness. It is further neces sary that the period of own vibration et the stroma elastic elements n and n be quite high in respect of that of the corresponding bar nso that the vibrations et n and 7i should not efi'ect materially the period of vibration o f bar n whieh period ought to be independent of the amount of the amplitude of n. The elen1ents n andn must therefore bc ratherrigid and heavy. But in spite of this the vibrating period of'bar n Sll0llld bc uniquely dependent on-the tension in spring m. This postulates rather heavyand poner fnl springs m which must be able to exert a pull; of 77 to kilograms. Frames I.: must, eonseqnently, be made largeah0ut 30 cm. x 15cm. The total bnlk of the box containing the vibrating apparatus is thus rather great. 4 .It may, however, be rednced by means of the following construction.

Referring to Fig.6 of-the drawing, there is shown a small standard vibrating clement having, a period 3: 'which may be rogulated 10 a nicety by means of a small spring 2. The standard 2 is maintained in a state 0*." uninterruptedvibration by means of an cloctrical source 3 havin'g one terminal connected to a small electromagnet 4 acting as a relay and arranged to.attract an elastieal contact leziring strip 7,.calleda rela strip. The

standard vibrating element 1 when Dot drawn by elcctromagnet4, contacts with adjustable screw The second terminal of 3 is connected through the relay electromagnet 6 to the fixed end of standardl. The current neeessary for-.-vibrating 1 being weak contacts on 1 and -at 5 need not be large. The standard vibrator 1 itself may also IK 1nadc of small and light construction. The rclay strip 7, heavier than 1, is placed in front of relay magnat 6 and provided with a contact large enough to carry current to ma nets b; This last mentioned contact seats. when the relay magnet 6 is not excited, against contact 1' connected through switrh c v to electromagnets b. Current for said electromagnets I) may be furnished by a separate source of current 8, as in the construction shown in Fig. 5. The contact 7, 7* will make and break in stop with the standard vibrator 1. As long as switch 0, operated by the-key, is not cl0sed, Vibration of 7 relatively to 7 takes place withont fiow of cnrrent. On the contrary, as soon as 6' closes, currnt of suitable periodical nature flows to electromagrnet b and causes string t to vibrate. Thc construction, briefly,- provides a relay system in which the dimensions of the standard" vibrators 1, and consequently the dimensions of the whole vibrator box, are very materially rcduced.

The eleetrieal rela strip 7 may be arrangcd so as to have a diferent own fundamental lIU period than the "standard vibrator 1 itself. If the freque'noy of 1 istaken as y 7 may be given a freqnency of- -4 y; A-frequency y for 1' cari be made to elflciently vibrate strip 7 having. frequny 4 y. -Buta frequency 4 y in 7 Cnables the latter t0 vibrate much*mor easily a string having a high fiequency for instance a frequency of 8iy than it could ifit had afrequency or" :yfionly. A fi'eqiiency 8 y isonlya second harmonie et 4 y but an 8th harmonie of y. As a result of this arrangement high notescan :b6=sustaihed*ina much stronger manner than would otherwise v be the case. Thus 6- may function to produce currents identioalto standard l or currents shwing a diflerent mairr -period. j relay electromagnet 6 may barrngd as shown in Fi 7 in order tobe excited by a current of frequency*y= andtovibrate at one pole a Contact strip 7 witlua 'freqnency"4y and at the bther pole* in anothercontact strip 8 t a frequenby ofonIy y. -The rela} magnet 6 maybesuppl'ed With pulsatory or alternating 'cnrxent suppliedfrom 'any convenient Source"for eXample, 'by a standard vibrator or buzzer 1 as showirin Fig.'6,or =it may be fed by a 3-electrode oscillator et as shown in Fig;7.- Imtlieiatter ca3e itis preferable to mount the=lamp cire;itsbn an iron bas in order tdobtai nilow freqeneiesi Frm the piecdiniti3 .evidexit that compact u1fios cntainingaminimm number of current s'orcsnnaybeanade npso as to be ezisily attaohable any stringed instrument for sustaihihg the Vibrations of its strings. Units' canbe niade up' of=vibrator boxes and otcurrent producing=boxes andquick ly assembled and attached toanypian,

The electromagnetic ibratprs such as I) maybe slidably niounted on appropriately deSigned baselemettts or=boards and adjusted quickly ontl1eltter in accordance with the spacing of the particular piano to which they are to be attached.

What I daim is 7 1. In an apparatusof the class described, the combination of a group of strings of different vibration frequency, means for producing "a source of current having a wave form corresponding to the combined traquencies of all the strings, and means connected to said current source for Vibrating any one string.

2. In an apparatus of the class described, the combination of a groupof strings of diffe1ent soumis havingfrequencics of Vibration which are harmonies of some 'fundamental, means for producing a source of current having a composite WaVe form corresponding tothe combined frequencies of the strings and means connected to said current source for vibrating any single string.

3.' l-nan apparatus of the class described, the combination ofa-grop of strings of diferent vibration frequenies, means for-produeing a source of-current having =a composite wave forin corresponding to the period of eachof the strings in saidrgroup{a circuit =connetingsaid cnrrent source to all of said strings, electromagnets for vibrating each stringand switehes for -diverting current from the source into any electromagnet.

4. In an apparatusof the class described, the combination ofa group of strings of different vibration frequencies, means for prodcing a'-source of. alternating current having a wavefornr including the -frequency of each string, electromag'nets for vibrating the strings, 'switches for diverting current into the electromagnets, each of said switches and electromagnets 'being conncted together in parallel across the terminals -of the current source.

5. The method'of producing sustained Vibrations in stringed instruments Wliicl1 comprises the st'eps'of produing a periodio electrio current having a waVe form which in-. cludes the periods-of ibrations of a group of strings, in distributing this current to all the strings constituting the-group, andin selecting from the composite-source'of currentthe freqnenc of current corresponding to the vibration frequency of any single-strinm :6. In an -apparatus0tthe Glass descrihed a group of strings having various vibration freqnencies, means for produeing asource of alternating crrent-of -desired wave-form, mens*fonvaxying the wave-form of the alternating current produced by said las t named means, a vibrator associated with each string, and meansconncting said source of current to each vibrator. 4

7. In an appratus of the class described a group of strings having; various vibration fiequencies, means for producing an alternating current having a wave-form including the vibration freqencies of each individual string, en electromagnet associated with each string, means for distributing the current produced by said-first named means to each of said elertromagnets, m-eans eperntive to connect said source of current to any single electromagnet, and electromagnetic means for assuring a tuned relation between the current flowing to any single electromagnet and the vibration freqnency of the string with which said electromagnet is associated.

In testimony whereof I have hercunto set my hand.

MARCEL TOURNIER. 

